Wood beams, posts, joists, balusters, and the like, referred to collectively herein as “members,” naturally shrink and expand due to the composition of the wood. A wood member can decrease and increase in length due to shrinkage and expansion in the direction of the wood grain. Frequent fluctuations of 3% are common, and fluctuations of as much as 18% may occur depending on the moisture content of the wood and the surrounding environment. Radial dimension changes also occur, although typically less drastically than length fluctuations. Despite the widespread knowledge of the natural dimensional fluctuations of wood members, conventional construction techniques largely ignore them, often to significant structural detriment.
In particular, it is often necessary to attach two wood members perpendicular to each other. Typically, the members are attached with a fastener, such as a nail or screw. Other known attachment devices include metal plate connectors that conform to the shape of the joint between the members. These metal plates are attached with fasteners to both members to create a “strong” or “rigid tie” that does not account for the dimensional fluctuations in the members. Once construction is complete, over time these fluctuations impart considerable tension forces on the members, the attachment devices, and related attached structural components. The tension forces may loosen the attachments across the joint, damage the wood, and otherwise warp the original shape and support capabilities of the constructed members.
While there are indeed requirements that some connections be rigid, in many instances the anticipated shrinkage of the wood member must be a consideration within the design and construction of wooden member connections. In particular, wood balustrades, as typically seen on balconies and decks, would benefit from a wood member connector that addresses the natural dimensional fluctuations. A balustrade is composed of several vertically-oriented balusters attached to top and bottom rails and spaced evenly apart so as to act as a guard rail or other barrier. Typically, the balusters are attached by nails or screws driven through each baluster at the upper and lower ends. The balusters then strain against the fasteners due to the dimensional fluctuations. Eventually, the fasteners begin to pull out, the wood splinters, or the contraction pulls the rails out of alignment, leading to significant safety hazards. A connector for balusters that accommodates the dimensional fluctuations is needed.
Therefore, it is an object of this invention to provide a device to attach two wood members to each other while accounting for the expected natural dimensional fluctuations of one or both members. It is a further object that the device provide a perpendicular attachment of the wood members. It is another object of the invention to provide a method of constructing structures with wood members that accounts for dimensional fluctuations in some or all of the wood members.